Anionic polymers composed of dicarboxylic acids and uses thereof

ABSTRACT

Biodegradable anionic polymers are disclosed which include recurring polymeric subunits preferably made up of dicarboxylic monomers such as maleic anhydride, itaconic anhydride or citraconic anhydride. Free radical polymerization is used in the synthesis of the polymers. The polymers may be complexed with ions and/or mixed with fertilizers or seeds to yield agriculturally useful compositions. The preferred products of the invention may be applied foliarly or to the earth adjacent growing plants in order to enhance nutrient uptake by the plants.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a divisional of application Ser. No. 09/799,210, filedMar. 5, 2001, which is hereby incorporated by reference herein.

BACKGROUND OF INVENTION

[0002] 1. Field of the Invention

[0003] The present invention is broadly concerned with novelsubstantially biodegradable and substantially water soluble anionicpolymers and derivatives thereof which have significant utility inagricultural applications, especially plant nutrition and related areas.More particularly, the invention is concerned with such polymers, aswell as methods of synthesis and use thereof, wherein the preferredpolymers have significant levels of anionic groups. The most preferredpolymers of the invention include recurring polymeric subunits made upof dicarboxylic (e.g., maleic acid or anhydride, itaconic acid oranhydride, and other derivatives thereof) monomers. The polymers may beapplied directly to the ground adjacent growing plants, complexed ontoions, applied directly to seeds, and/or mixed with or coated withphosphate-based fertilizers to provide improved plant nutritionproducts.

[0004] 2. Description of the Prior Art

[0005] Lignosulfonates, polyacrylates, polyaspartates and relatedcompounds have become known to the art of agriculture as materials thatfacilitate nutrient absorption. All of them suffer from significantdisadvantages, which decrease their utility in comparison to the artdiscussed herein and limit performance.

[0006] Lignosulfonates are a byproduct of paper pulping; they arederived from highly variable sources. They are subject to large,unpredictable variations in color, physical properties, and performancein application areas of interest for this invention.

[0007] Polyacrylates and polymers containing appreciable levels thereofcan be prepared with good control over their composition andperformance.

[0008] They are stable to pH variations. However, polyacrylates havejust one carboxylate per repeat unit and they suffer from a verysignificant limitation in use, namely that they are not biodegradable.As a result, their utility for addressing the problems remedied by theinstant invention is low.

[0009] Polyaspartates are biodegradable, but are very expensive, and arenot stable outside a relatively small pH range of about 7 to about 10.They usually have very high color, and incorporate amide groups, whichcauses difficulties in formulating them. Additionally, polyaspartateshave just one carboxylate per repeat unit and are therefore not a partof the present invention.

[0010] Preparation of itaconic acid homopolymers has been known to theart of polymer chemistry for an extended period of time. Severalapproaches to making it exist. One approach is by the directpolymerization of itaconic acid and/or its salts in aqueous or organicsolutions under a wide range of conditions. Such reactions are describedin the Journal of Organic Chemistry, Vol. 24, pg. 599 (1959) theteachings of which are incorporated by reference herein. Anotherapproach is to begin with esters of itaconic acid, polymerize them undersuitable conditions, and then hydrolyze the ester groups off in order toliberate polyitaconic acid. This approach is described in U.S. Pat. No.3,055,873, the teachings of which are hereby incorporated by reference.Additionally, a very good summary of many aspects of the prior art isfound in U.S. Pat. No. 5,223,592, the teachings of which are herebyincorporated by reference.

[0011] It will thus be seen that the prior art fails to disclose orprovide polymers which can be synthesized using a variety of monomersand techniques in order to yield end products which are substantiallybiodegradable, substantially water soluble, and have wide applicabilityfor agricultural uses. Moreover, no prior art or combination of priorart discloses preparation of itaconic acid copolymers with one or moreorganic acids containing at least one olefinic bond and at least twocarboxylic acid groups. Furthermore, while the prior art does disclose avariety of methods for making polyitaconic acid homopolymer, it fails toteach, disclose, or suggest the utility such materials unexpectedly havefor a wide variety of agricultural uses.

SUMMARY OF INVENTION

[0012] The present invention overcomes the problems outlined above andprovides a new class of anionic polymers having a variety of uses, e.g.,for enhancing takeup of nutrient by plants or for mixture withconventional phosphate-based fertilizers to provide an improvedfertilizer product. Advantageously, the polymers are biodegradable, inthat they degrade to environmentally innocuous compounds within arelatively short time (up to about 1 year) after being in intimatecontact with soil. That is to say, the degradation products arecompounds such as CO₂ and H₂O or the degradation products are absorbedas food or nutrients by soil microorganisms and plants. Similarly,derivatives of the polymers and/or salts of the polymers (e.g. ammoniumsalt forms of the polymer) also degrade within a relatively short time,during which significant fractions of the weight of the polymer arebelieved to be metabolized by soil organisms.

[0013] Broadly speaking, the anionic polymers of the invention includerecurring polymeric subunits made up of at least two different moietiesindividually and respectively taken from the group consisting of whathave been denominated for ease of reference as B and C moieties;alternately, the polymers may be formed from recurring C moieties. Thus,exemplary polymeric subunits may be BC, CB, CC, or any other combinationof B, and C moieties; moreover, in a given polymer different polymericsubunits may include different types of moieties, e.g., in an BCrecurring polymeric unit polymer, the B moiety may be different indifferent units.

[0014] In detail, moiety B is of the general formula

[0015] wherein each R₇ is individually and respectively selected fromthe group consisting of H, OH, C₁-C₃₀ straight, branched chain andcyclic alkyl or aryl groups, C₁-C₃₀ straight, branched chain and cyclicalkyl or aryl formate (C₀), acetate (C₁), propionate (C₂), butyrate(C₃), etc. up to C₃₀ based ester groups, R′CO₂ groups, OR′ groups andCOOX groups, wherein R′ is selected from the group consisting of C₁-C₃₀straight, branched chain and cyclic alkyl or aryl groups and X isselected from the group consisting of H, the alkali metals, NH₄ and theC₁-C₄ alkyl ammonium groups, R₃ and R₄ are individually and respectivelyselected from the group consisting of H, C₁-C₃₀ straight, branched chainand cyclic alkyl or aryl groups, R₅, R₆, R₁₀ and R₁₁ are individuallyand respectively selected from the group consisting of H, the alkalimetals, NH₄ and the C₁-C₄ alkyl ammonium groups, Y is selected from thegroup consisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V and Ca, and R₈ andR₉ are individually and respectively selected from the group consistingof nothing (i.e., the groups are non-existent), CH₂, C₂H₄, and C₃H₆,each of said moieties having or being modified to have a total of twoCOO groups therein.

[0016] As can be appreciated, the polymers of the invention can havedifferent sequences of recurring polymeric subunits as defined above(For example, a polymer comprising B and C subunits may include allthree forms of B subunit and all three forms of C subunit. However, forreasons of cost and ease of synthesis, the most useful polymers includerecurring polymeric subunits made up of B and C moieties. In the case ofthe polymer made up of B and C moieties, R₅, R₆, R₁₀, and R₁₁ areindividually and respectively selected from the group consisting of H,the alkali metals, NH₄, and the C₁-C₄ alkyl ammonium groups. Thisparticular polymer is sometimes referred to as a butanedioicmethylenesuccinic acid copolymer and can include various salts andderivatives thereof. The most preferred polymers of the invention arecomposed of recurring polymeric subunits formed of B and C moieties andhave the generalized formula

[0017] Preferred forms of this polymer have R₅, R₆, R₁₀, and R₁₁individually and respectively selected from the group consisting of H,the alkali metals, NH₄, and the C₁-C₄ alkyl ammonium groups. Otherpreferred forms of this polymer are capable of having a wide range ofrepeat unit concentrations in the polymer. For example, polymers havingvarying ratios of B:C (e.g., 10:90, 60:40, 50:50 and even 0:100) arecontemplated and embraced by the present invention. Such polymers wouldbe produced by varying monomer amounts in the reaction mixture fromwhich the final product is eventually produced and the B and C typerepeating units may be arranged in the polymer backbone in random orderor in an alternating pattern.

[0018] The polymers of the invention may have a wide variety ofmolecular weights, ranging for example from 500-5,000,000, dependingchiefly upon the desired end use. Additionally, n can range from about1-10,000 and more preferably from about 1-5,000.

[0019] For purposes of the present invention, it is preferred to usedicarboxylic acids, precursors and derivatives thereof for the practiceof the invention. For example, terpolymers containing mono anddicarboxylic acids with vinyl esters and vinyl alcohol are contemplated,however, polymers incorporating dicarboxylic acids were unexpectedlyfound to be significantly more useful for the purposes of thisinvention. This finding was in contrast to the conventional teachingsthat mixtures of mono and dicarboxylates were superior in applicationspreviously suggested for mono-carboxylate polymers. Thus, the use ofdicarboxylic acid derived polymers for agricultural applications isunprecedented and produced unexpected results. It is understood thatwhen dicarboxylic acids are mentioned herein, various precursors andderivatives of such are contemplated and well within the scope of thepresent invention. Put another way, copolymers of the present are madeup of monomers bearing at least two carboxylic groups or precursorsand/or derivatives thereof. The polymers of the invention may have awide variety of molecular weights, ranging for example from500-5,000,000, more preferably from about 1,500-20,000, dependingchiefly upon the desired end use.

[0020] In many applications, and especially for agricultural uses, thepolymers of the invention may be mixed with or complexed with a metal ornon-metal ion, and especially ions selected from the group consisting ofFe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V, Cr, Si, B, and Ca. Alternatively,polymers containing, mixed with or complexed with such elements may beformulated using a wide variety of methods that are well known in theart of fertilizer formulation. Examples of such alternative methodsinclude, forming an aqueous solution containing molybdate and the sodiumsalt of polymers in accordance with the invention, forming an aqueoussolution which contains a zinc complex of polymers in accordance withthe present invention and sodium molybdate, and combinations of suchmethods. In these examples, the presence of the polymer in soil adjacentgrowing plants would be expected to enhance the availability of theseelements to these growing plants. In the case of Si and B, the elementwould merely be mixed with the polymer rather than having a coordinatemetal complex formation. However, in these cases, the availability ofthese ions would be increased for uptake by growing plants and will betermed “complexed” for purposes of this application.

[0021] The polymers hereof (with or without complexed ions) may be useddirectly as plant growth enhancers. For example, such polymers may bedispersed in a liquid aqueous medium and applied foliarly to plantleaves or applied to the earth adjacent growing plants. It has beenfound that the polymers increase the plant's uptake of bothpolymer-borne metal nutrients and ambient non-polymer nutrients found inadjacent soil. In such uses, plant growth-enhancing amounts ofcompositions comprising the above-defined polymers are employed, eitherin liquid dispersions or in dried, granular form. Thus, application ofpolymer alone results in improved plant growth characteristics,presumably by increasing the availability of naturally occurring ambientnutrients. Typically, the polymers are applied at a level of from about0.001 to about 100 lbs. polymer per acre of growing plants, and morepreferably from about 0.005 to about 50 lbs. polymer per acre, and stillmore preferably from about 0.01 to about 2 lbs.

[0022] In other preferred uses, the polymers may be used to formcomposite products where the polymers are in intimate contact withfertilizer products including but not limited to phosphate-basedfertilizers such as monoammonium phosphate (MAP), diammonium phosphate(DAP), any one of a number of well known N—P—K fertilizer products,and/or fertilizers containing nitrogen materials such as ammonia(anhydrous or aqueous), ammonium nitrate, ammonium sulfate, urea,ammonium phosphates, sodium nitrate, calcium nitrate, potassium nitrate,nitrate of soda, urea formaldehyde, metal (e.g. zinc, iron) ammoniumphosphates; phosphorous materials such as calcium phosphates (normalphosphate and super phosphate), ammonium phosphate, ammoniated superphosphate, phosphoric acid, superphosphoric acid, basic slag, rockphosphate, colloidal phosphate, bone phosphate; potassium materials suchas potassium chloride, potassium sulfate, potassium nitrate, potassiumphosphate, potassium hydroxide, potassium carbonate; calcium materials,such as calcium sulfate, calcium carbonate, calcium nitrate; magnesiummaterials, such as magnesium carbonate, magnesium oxide, magnesiumsulfate, magnesium, hydroxide; sulfur materials such as ammoniumsulfate, sulfates of other fertilizers discussed herein, ammoniumthiosulfate, elemental sulfur (either alone or included with or coatedon other fertilizers); micronutrients such as Zn, Mn, Cu, Fe, and othermicronutrients discussed herein; oxides, sulfates, chlorides, andchelates of such micronutrients (e.g., zinc oxide, zinc sulfate and zincchloride); such chelates sequestered onto other carriers such as EDTA;boron materials such as boric acid, sodium borate or calcium borate; andmolybdenum materials such as sodium molybdate. As known in the art,these fertilizer products can exist as dry powders/granules or as watersolutions.

[0023] In such contexts, the polymers may be co-ground with thefertilizer products, applied as a surface coating to the fertilizerproducts, or otherwise thoroughly mixed with the fertilizer products.Preferably, in such combined fertilizer/polymer compositions, thefertilizer is in the form of particles having an average diameter offrom about powder size (less than about 0.001 cm) to about 10 cm, morepreferably from about 0.1 cm to about 2 cm, and still more preferablyfrom about 0.15 cm to about 0.3 cm. The polymer is present in suchcombined products at a level of from about 0.001 g to about 20 g polymerper 100 g phosphate-based fertilizer, more preferably from about 0.1 gto about 10 g polymer per 100 g phosphate-based fertilizer, and stillmore preferably from about 0.5 g to about 2 g polymer per 100 gphosphate-based fertilizer. Again, the polymeric fraction of suchcombined products may include the polymers defined above, or suchpolymers complexed with the aforementioned ions. In the case of thecombined fertilizer/polymer products, the combined product is applied ata level so that the polymer fraction is applied at a level of from about0.001 to about 20 lbs. polymer per acre of growing plants, morepreferably from about 0.01 to about 10 lbs polymer per acre of growingplants, and still more preferably from about 0.5 to about 2 lbs polymerper acre of growing plants. The combined products can likewise beapplied as liquid dispersions or as drygranulated products, at thediscretion of the user. When polymers in accordance with the presentinvention are used as a coating, the polymer comprises between about0.005% and about 15% by weight of the coated fertilizer product, morepreferably the polymer comprises between about 0.01% and about 10% byweight of the coated fertilizer product, and most preferably between0.5% and about 1% by weight of the coated fertilizer product. It hasbeen found that polymer-coated fertilizer products obtain highlydesirable characteristics due to the alteration of mechanical andphysical properties of the fertilizer.

[0024] Additionally, use of polymers in accordance with the presentinvention increases the availability of phosphorus and other commonfertilizer ingredients and decreases nitrogen volatilization, therebyrendering ambient levels of such plant nutrient available for uptake bygrowing plants. In such cases, the polymer can be applied as a coatingto fertilizer products prior to their introduction into the soil. Inturn, plants grown in soil containing such polymers exhibit enhancedgrowth characteristics.

[0025] Another alternative use of polymers in accordance with thepresent invention includes using the polymer as a seed coating. In suchcases, the polymer comprises at least about 0.005% and about 15% byweight of the coated seed, more preferably, the polymer comprisesbetween about 0.01% and about 10% by weight of the coated seed, and mostpreferably between 0.5% and about 1% by weight of the coated seed. Useof the polymer as a seed coating provides polymer in close proximity tothe seed when planted so that the polymer can exert its beneficialeffects in the environment where it is most needed. That is to say thatthe polymer provides an environment conducive to enhanced plant growthin the area where the effects can be localized around the desired plant.In the case of seeds, the polymer coating provides an enhancedopportunity for seed germination and subsequent plant growth due to thedecrease in nitrogen volatilization an increase in plant nutrientavailability which is provided by the polymer.

[0026] In general, the polymers of the invention are made by freeradical polymerization serving to convert selected monomers into thedesired polymers with recurring polymeric subunits. Such polymers may befurther modified to impart particular structures and/or properties. Avariety of techniques can be used for generating free radicals, such asaddition of peroxides, hydroperoxides, azo initiators, persulfates,percarbonates, per-acid, charge transfer complexes, irradiation (e.g.,UV, electron beam, X-ray, gamma-radiation and other ionizing radiationtypes), and combinations of these techniques. Of course, an extensivevariety of methods and techniques are well known in the art of polymerchemistry for initiating free-radical polymerizations. Those enumeratedherein are but some of the more frequently used methods and techniques.Any suitable technique for performing free-radical polymerization islikely to be useful for the purposes of practicing the presentinvention.

[0027] The polymerization reactions are carried out in a compatiblesolvent system, namely a system which does not unduly interfere with thedesired polymerization, using essentially any desired monomerconcentrations. A number of suitable aqueous or non-aqueous solventsystems can be employed, such as ketones, alcohols, esters, ethers,aromatic solvents, water and mixtures thereof. Water alone and the lower(C₁-C₄) ketones and alcohols are especially preferred, and these may bemixed with water if desired. In some instances, the polymerizationreactions are carried out with the substantial exclusion of oxygen, andmost usually under an inert gas such as nitrogen or argon. There is noparticular criticality in the type of equipment used in the synthesis ofthe polymers, i.e., stirred tank reactors, continuous stirred tankreactors, plug flow reactors, tube reactors and any combination of theforegoing arranged in series may be employed. A wide range of suitablereaction arrangements are well known to the art of polymerization.

[0028] In general, the initial polymerization step is carried out at atemperature of from about 0Â° C. to about 120Â° C. (more preferably fromabout 30Â° C. to about 95Â° C. for a period of from about 0.25 hours toabout 24 hours and even more preferably from about 0.25 hours to about 5hours). Usually, the reaction is carried out with continuous stirring.

[0029] Thereafter, the completed polymer may be recovered as a liquiddispersion or dried to a solid form. Additionally, in many cases it ispreferred to react the polymer with an ion such as Fe, Mn, Mg, Zn, Cu,Ni, Co, Mo, V, Cr, and Ca to form a coordinate metal complex. Techniquesfor making metal-containing polymer compounds are well known to thoseskilled in the art. In some of these techniques, a metal's oxide,hydroxide, carbonate, salt, or other similar compound may be reactedwith the polymer in acid form. These techniques also include reacting afinely divided free metal with a solution of an acid form of a polymerdescribed or suggested herein. Additionally, the structures of complexesor salts of polymers with metals in general, and transition metals inparticular, can be highly variable and difficult to precisely define.Thus, the depictions used herein are for illustrative purposes only andit is contemplated that desired metals or mixtures of such are bonded tothe polymer backbone by chemical bonds. Alternatively, the metal may bebonded to other atoms in addition to those shown. For example, in thecase of the structure shown herein for the second reactant, there may beadditional atoms or functional groups bonded to the Y. These atomsinclude, but are not limited to, oxygen, sulfur, halogens, etc. andpotential functional groups include (but are not limited to) sulfate,hydroxide, etc. It is understood by those skilled in the art ofcoordination compound chemistry that a broad range of may be formeddepending upon the preparation protocol, the identity of the metal, themetal's oxidation state, the starting materials, etc. In the case of Siand B ions, the polymer is merely mixed with these ions and does notform a coordinate complex. However, the availability of these ions togrowing plants is increased. It is also noted that it is possible toreact the monomers used to form the polymer with ions in similar waysbefore polymerization. In other words, the monomers can be reacted withmetals (including metals in their pure state, as oxides, carbonates,hydroxides, or other suitable metal-containing compounds) or ions insuch a way as to result in the formation of a salt, a complex, or asimilar molecule. It is also contemplated that reaction of monomers witha metal can be followed by their polymerization and subsequent reactionwith a further portion of metal.

[0030] In more detail, the preferred method for polymer synthesiscomprises the steps of providing a reaction mixture comprising at leasttwo different reactants selected from the group consisting of first andsecond reactants. The first reactant is of the general formula

[0031] With reference to the above formulae, each R₇ is individually andrespectively selected from the group consisting of H, OH, C₁-C₃₀straight, branched chain and cyclic alkyl or aryl groups, C₁-C₃₀straight, branched chain and cyclic alkyl or aryl formate (C₀), acetate(C₁), propionate (C₂), butyrate (C₃), etc. up to C₃₀ based ester groups,R′CO₂ groups, OR′ groups and COOX groups, wherein R′ is selected fromthe group consisting of C₁-C₃₀ straight, branched chain and cyclic alkylor aryl groups and X is selected from the group consisting of H, thealkali metals, NH₄ and the C₁-C₄ alkyl ammonium groups, R₃ and R₄ areindividually and respectively selected from the group consisting of H,C₁-C₃₀ straight, branched chain and cyclic alkyl or aryl groups, R₅, R₆,R₁₀ and R₁₁ are individually and respectively selected from the groupconsisting of H, the alkali metals, NH₄ and the C₁-C₄ alkyl ammoniumgroups, Y is selected from the group consisting of Fe, Mn, Mg, Zn, Cu,Ni, Co, Mo, V and Ca, and R₈ and R₉ are individually and respectivelyselected from the group consisting of nothing (i.e., the groups arenon-existent), CH₂, C₂H₄, and C₃H₆, each of said moieties having orbeing modified to have a total of two COO groups therein.

[0032] Selected monomers and reactants are dispersed in a suitablesolvent system and placed in a reactor. The polymerization reaction isthen carried out to obtain an initial polymerized product having thedescribed recurring polymeric subunits. Put another way, the generalreaction proceeds by dissolving monomers (e.g., maleic anhydride anditaconic acid) in acetone and/or water in either equimolar ornon-equimolar amounts. A free radical initiator is then introduced andcopolymerization takes place in solution. After the reaction is completeand a major fraction of the monomer has been reacted, the resultingsolution for this particular example is a maleic acid-itaconic acidcopolymer. Of course, if all monomers have not undergone polymerization,the resulting solution will contain a small portion of monomers which donot affect later use of the polymer.

[0033] Another important aspect of the present invention is theenhancement of dust control when a polymer in accordance with thepresent is applied as a coating to a fertilizer. It has been found thatcoating the fertilizer with a polymer in accordance with the presentinvention greatly decreases the generation of dust. Such adust-controlling property of polymers in accordance with the presentinvention was entirely unexpected yet provides a distinct advance in thestate of the art in that, typically, a separate dust-controllingsubstance is applied to fertilizers prior to their application in afield. Generally, the polymer will be applied as a coating to thesurface of the fertilizer in order to form a substantially coatedfertilizer product. As noted above, the polymer may comprise betweenabout 0.005% to about 15% by weight of the coated fertilizer product,however, for dust control, it is preferred to have the coating level beup to about 0.5% w/w as it has been demonstrated that coating levels aslow as 0.5% w/w completely inhibit the generation of dust. Of course,the coating level can be increased to levels greater than 0.5% w/w inorder to enhance other beneficial properties of the polymer while stillcompletely inhibiting dust generation. Thus, the present invention willeliminate the need for this separate dust-controlling substance whilestill contributing all of the beneficial properties described above.

[0034] Again, it is important to note that the aforementioned methodsand procedures are merely preferred methods of practicing the presentinvention and those skilled in the art understand that a large number ofvariations and broadly analogous procedures can be carried out using theteachings contained herein. For example, polymers may be used as is (inthe acid form) or further reacted with various materials to make saltsand/or complexes. Furthermore, complexes or salts with various metalsmay be formed by reacting the acid form with various oxides, hydroxides,carbonates, and free metals under suitable conditions. Such reactionsare well known in the art and include (but are not limited to) varioustechniques of reagent mixing, monomer and/or solvent feed, etc. Onepossible technique would be gradual or stepwise addition of an initiatorto a reaction in progress. Other potential techniques include theaddition of chain transfer agents, free radical initiator activators,molecular weight moderators/control agents, use of multiple initiators,initiator quenchers, inhibitors, etc. Of course, this list is notcomprehensive but merely serves to demonstrate that there are a widevariety of techniques available to those skilled in the art and that allsuch techniques are embraced by the present invention.

BRIEF DESCRIPTION OF DRAWINGS

[0035]FIG. 1 is a graph illustrating the percentage of nitrogen andammonia lost from untreated urea over a sixteen day testing period; and

[0036]FIG. 2 is a graph illustrating the percentage of nitrogen andammonia lost over a sixteen day testing period from urea coated withpolymer.

DETAILED DESCRIPTION

[0037] The following examples set forth techniques for the synthesis ofpolymers in accordance with the invention, and various uses thereof. Itis to be understood that these examples are provided by way ofillustration only and nothing therein should be taken as a limitationupon the overall scope of the invention.

EXAMPLE 1

[0038] Acetone (803 g), maleic anhydride (140 g), itaconic acid (185 g)and benzoyl peroxide (11 g) were stirred together under inert gas in areactor. The reactor provided included a suitably sized cylindricaljacketed glass reactor with mechanical agitator, a contents temperaturemeasurement device in contact with the contents of the reactor, an inertgas inlet, and a removable reflux condenser. This mixture was heated bycirculating heated oil in the reactor jacket and stirred vigorously atan internal temperature of about 65-70Â° C. This reaction was carriedout over a period of about 5 hours. At this point, the contents of thereaction vessel were poured into 300 g water with vigorous mixing. Thisgave a clear solution. The solution was subjected to distillation atreduced pressure to drive off excess solvent and water. After sufficientsolvent and water have been removed, the solid product of the reactionprecipitates from the concentrated solution, and is recovered. Thesolids are subsequently dried in vacuo. A schematic representation ofthis reaction is shown below.

EXAMPLE 2

[0039] This reaction was carried out in equipment similar to that usedin Example 1 above. The following procedure was followed:847 g purifiedwater was placed into the reactor. Next, 172 g itaconic acid and 130 gmaleic anhydride were added with vigorous stirring. This mixture washeated to about 85-90Â° C., at which temperature this mixture exists asa clear solution. When the mixture reached the desired temperature, 15 gof potassium persulfate was added to the solution. The reaction mixturewas allowed to stir for 3 hours, and a second portion of persulfate,equal to the first, was added, and allowed to react for a further 3hours. Product was isolated in the same manner as described forExample 1. A schematic representation of this reaction is shown below

EXAMPLE 3

[0040] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was diluted with water to give a 10% w/w solution.Then, 6.62 g ZnO was added to 200 g of this solution. The oxidedissolved in the liquid with stirring. This solution was then dried to awhite highly water-soluble powder.

EXAMPLE 4

[0041] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was diluted with water to give a 30% w/w solution.6.66 g CuO was then added to 260 g of this solution. The oxide dissolvedin the liquid with stirring and heating to about 60 degrees C. Thissolution was then dried to a green-colored highly water-soluble powder.

EXAMPLE 5

[0042] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was diluted with water to give a 10% w/w solution.To 200 g of this solution, 5.76 g MnO₂ was added. The oxide dissolved inthe liquid with stirring and heating to about 60 degrees C. Thissolution was then dried to a pink-colored, highly water-soluble powder.

EXAMPLE 6

[0043] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was diluted with water to give a 10% w/w solution.Next, 3.28 g MgO was added to 200 g of this solution. The oxidedissolved in the liquid with stirring. This solution was then dried to awhite highly water-soluble powder.

EXAMPLE 7

[0044] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was diluted with water to give a 25% w/w solution.2.96 g V₂O₅ was then added to 240 g of this solution. The oxidedissolved in the liquid with stirring. This solution was then dried to agreen highly water-soluble powder.

EXAMPLE 8

[0045] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was diluted with water to give a 10% w/w solution.To 200 g of this solution, 3.03 g metallic Fe in finely powdered formwas added. The metal dissolved in the liquid with stirring. Thissolution was then dried to a yellow highly water-soluble powder.

EXAMPLE 9

[0046] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was diluted with water to give a 10% w/w solution.To 200 g of this solution, 8.14 g CaCO₃ was added. The carbonatedissolved in the liquid with stirring. This solution was then dried to awhite highly water-soluble powder.

EXAMPLE 10

[0047] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was neutralized to a pH of 7 with aqueous NaOH(40% w/w). The resulting solution was dried to give a white highlywater-soluble powder.

EXAMPLE 11

[0048] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was neutralized to a pH of 7 with aqueous KOH (30%w/w). The resulting solution was dried to give a white highlywater-soluble powder.

EXAMPLE 12

[0049] The procedure of Example 2 was followed, but the product was notisolated. Instead, it was neutralized to a pH of 3 with anhydrousammonia gas that was introduced into the solution by means of a gasdispersion tube. The resulting solution was dried to give a white highlywater-soluble powder.

EXAMPLE 13

[0050] This example followed the procedure of Example 12. However, theanhydrous ammonia gas was introduced into the solution prior to theaddition of the initiator. Again, the solution was neutralized to a pHof 3. Thus, the neutralization step partially neutralized the monomersrather than the polymer. The initiator used for this example wasammonium persulfate and the reaction scheme is depicted below.

[0051] In this scheme, the first three steps are just an extensiveelaboration of the neutralization of the water-monomer mixture withanhydrous ammonia to a pH of 3. Such a reaction is equally describableby depicting a reaction scheme using starting materials includingitaconic acid, maleic anhydride, anhydrous ammonia, and water whichresults in the product shown at the far right end in step 3. The saltsas drawn are theoretical, however, this does show that the monomers arenot completely neutralized nor are they completely un-neutralized. Ofcourse, it is well within the scope of the present invention to have themonomers completely neutralized or completely un-neutralized by theaddition of any suitable base as well as having a wide range of B:Cmonomer ratios.

EXAMPLE 14

[0052] This reaction was carried out in equipment similar to that usedin Example 1 above. The following procedure was followed:1990 g purifiedwater was placed into the reactor and 1260 g itaconic acid and 950 gmaleic anhydride was added with vigorous stirring. This mixture was thenheated to about 75 C, at which temperature this mixture as a clearsolution. When the mixture reached the desired temperature, 270 gpotassium persulfate was added stepwise to the solution. Persulfateaddition was conducted at 1 hour intervals in amount of 30 g peraddition. Product was isolated in the same manner as described inExample 1.

EXAMPLE 15

[0053] This reaction was carried out in the same fashion as Example 14,but ammonium persulfate was used. The total amount of persulfate was 225g.

EXAMPLE 16

[0054] In this example, the effect of polymer upon volatilization ofammonia from urea was determined. A 100 g sample of granular urea wascoated with the H polymer by adding 1% polymer and 3.5 ml liquid (H₂O)to the urea and shaking the mixture to achieve a uniform coating on theurea. Clay (kaolanite clay) was then added to absorb the excess H₂O.Polymer coated urea and uncoated urea were placed in chambers that wereoptimized for the volatilization of ammonia. The polymer coated urea anduncoated urea were then analyzed for content over a sixteen day period.

[0055]FIG. 1 illustrates the amount of nitrogen and ammonia lost fromthe urea over the sixteen day testing period. This loss totaled 37.4%.In comparison, FIG. 2 illustrates the amount of ammonia and nitrogenlost from the urea coated with the polymer. The polymer coated ureaexperienced a 54% reduction of nitrogen and ammonia loss in comparisonto the uncoated urea. Thus, the polymer coating greatly decreasednitrogen volatilization. Such a decrease in volatilization would alsoresult from the polymer and urea being co-ground together or by havingthe polymer in close proximity to the urea in soil.

EXAMPLE 17

[0056] In this example the effects of liquid ammoniated phosphates andpolymer-treated liquid ammoniated phosphates on acid soils having a highphosphorous fixation capacity period were compared. Untreated liquidammoniated phosphate (10-34-0) and liquid ammoniated phosphate with 1%by weight polymer and liquid ammoniated phosphate with 2% by weightammoniated polymer were applied in a band (2 inches below and 2 inchesbeneath) in the seed row. The polymer used for this experiment was thesodium form. Corn was grown to the six leaf stage and then harvested.The plants were dried, and the dry weight recorded. Results of thisexperiment are given in Table 1.

[0057] The acid soil was very responsive to the 10-34-0 controlled andcorn grown in this soil experienced a 151% increase in dry weight. Incomparison, the addition of 1% polymer increased corn growth by anadditional 19% and addition of the 2% polymer increased corn growth by26% in comparison to the. 10-34-0 control. Thus, addition of the polymerhad advantageous effects on the growth of corn TABLE 1 Acid Soil DryMatter/grams No P Control 1.67 10-34-0 Control (No Polymer) 4.20 10-34-01% Polymer 5.00 10-34-0 2% Polymer 5.30

EXAMPLE 18

[0058] In this example the efficiency of different salts of the anionicpolymer as a coating on phosphate fertilizer was evaluated. Polymercoatings were applied on a 1% by weight basis onto MAP. The test cropfor this experiment was corn and the polymer used was a polymer formedby B and C monomers. All phosphorous treatments were banded 2 inchesbelow and 2 inches away from the seed rows. The acid in calcareous soilsused in this experiment are both known to fix phosphorous fertilizer,thereby limiting the growth of crops. The corn was harvested at the sixleaf stage and dry weights were determined as an indication as theefficiency of the coatings on phosphorous uptake and resultant corngrowth. Results of this experiment are given below in Table 2. Table 2shows that both the hydrogen and ammonium salts of the polymer wereeffective at increasing corn growth when combined with MAP. The acidcontrol (untreated MAP) produced 294% more dry matter than the controlwhich did not include MAP. These results illustrate that the soil isvery responsive to phosphorous. When the MAP was coated with the anionicpolymer charged neutralized with hydrogen, dry matter yields wereincreased by 41.9%. The calcareous control (untreated MAP) produced 128%more dry matter than the control which did not include any MAP. The MAPtreated with the anionic polymer charge neutralized with ammonium,produced 15.9% more dry matter than the MAP control TABLE 2 Acid SoilCalcareous Soil (Dry Matter/grams) (Dry Matter/grams) No P Control (noMAP) 4.72 12.4 MAP Control 18.6 28.3 1% Hydrogen Polymer 26.4 1%Ammonium Polymer 32.81

EXAMPLE 19

[0059] In this example, the effect of a zinc polymer on corn seedlinggrowth was determined. A 21% zinc-polymer was prepared and applied tocorn seeds at a rate of eight ounces per 100 pounds of seed. The seeds,were planted in six inch pots and allowed to grow until they reached thefour leaf stage. The soil was calcareous and had low zinc availability.At the four leaf stage, plants were harvested and dried, then the dryweights were determined. Dry weights increased by 29% on the plantswhere the zinc-polymer was applied to the seed versus the control.

EXAMPLE 20

[0060] This example tested the dust controlling effects of the polymeron fertilizer particles. The test used was an abrasion resistance testbased on the rotary drum method. This tests the resistance to dust andfines formation resulting from granule-granule and granule-equipmentcontact. It is useful in determining material losses; handling, storage,and application properties; and pollution control equipmentrequirements. A sample was first screened manually to separate out afraction containing approximately minus 3.35 mm to 1.00 mm granules. Arepresentative 100 cm3 portion of the minus 3.35- plus 1.00-mm fractionwas then used in the test. A 20 g portion of this was then weighed outand placed in a 100 ml rectangular polyethylene bottle together with 10stainless steel balls measuring 7.9 mm in diameter and having a totalweight of 20.0 g. The bottle was then closed and manually shaken forfive minutes. In order to ensure uniform shaking for all samples in ananalytical run, all sample bottles were taped together into one block.At the end of the run, the balls were removed manually, and the bottlecontents examined. Fines were separated manually and weighed. Resultsfrom this example are given below in Table 3 which clearly shows thatthe polymers of the present invention are highly useful as a coating forMAP fertilizer particles in order to enhance abrasion resistance anddecrease dust generation. The reference to the “H” polymer form refersto the fact that the carboxylic acid groups are still intact TABLE 3Coating Level, % Dust Percent after Fertilizer Type Coating W/W, As-IsShaking Granular MAP None N/A 0.43 Granular MAP ARR-MAZ KGA500 0.52 0.29Granular MAP High charge polymer, mostly H 0.5 none form, 60% solidsGranular MAP High charge polymer, mostly H 1 none form, 60% solidsGranular MAP High charge polymer, mostly H 1.5 none form, 60% solids

1. A method of forming a polymer comprising the steps of: providing areaction mixture comprising at least two different reactants selectedfrom the group consisting of first and second or a mixture of saidsecond reactants, wherein said first reactant is of the general formula

and said second reactant is of the general formula

wherein each R₇ is individually an d respectively selected from thegroup consisting of H, OH, C₁-C₃₀ straight, branched chain and cyclicalkyl or aryl groups, C₁-C₃₀ straight, branched chain and cyclic alkylor aryl formate (C₀), acetate (C₁), propionate (C₂), butyrate (C₃), etc.up to C₃₀ based ester groups, R′CO₂ groups, OR′ groups and COOX groups,wherein R′ is selected from the group consisting of C₁-C₃₀ straight,branched chain and cyclic alkyl or aryl groups and X is selected fromthe group consisting of H, the alkali metals, NH₄ and the C₁-C₄ alkylammonium groups, R₃ and R₄ are individually and respectively selectedfrom the group consisting of H, C₁-C₃₀ straight, branched chain andcyclic alkyl or aryl groups, R₅, R₆, R₁₀ and R₁₁ are individually andrespectively selected from the group consisting of H, the alkali metals,NH₄ and the C₁-C₄ alkyl ammonium groups, Y is selected from the groupconsisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V and Ca, and R₈ and R₉are individually and respectively selected from the group consisting ofnothing (i.e., the groups are non-existent), CH₂, C₂H₄, and C₃H₆, eachof said moieties having or being modified to have a total of two COOgroups therein; and polymerizing said reaction mixture to form a polymerhaving recurring polymeric subunits therein with carboxyl-containinggroups.
 2. The method of claim 1, said first reactant being maleicanhydride and said second reactant being itaconic acid.
 3. The method ofclaim 1, said polymerization step being carried out by generating freeradicals in said reaction mixture.
 4. The method of claim 3, said freeradical generation step comprising the step of adding a peroxide to saidreaction mixture.
 5. The method of claim 3, said free radical generationstep comprising the step of subjecting said reaction mixture to UVlight.
 6. The method of claim 3, said free radical generation stepcomprising the step of adding a persulfate to said reaction mixture. 7.The method of claim 1, said reaction mixture being formed in a solventselected from the group consisting of water and acetone.
 8. The methodof claim 1, said polymerization step being carried out at a temperatureof from about 0Â° C. to about 120Â° C. for a period of from about 0.25hours to about
 24. hours.
 9. The method of claim 1, said polymerizationstep being carried out under an inert gas atmosphere.
 10. The method ofclaim 1, including the step of drying said polymer to a solid form. 11.The method of claim 1, including the step of reacting said polymer withan ion to form a complex with the polymer.
 12. The method of claim 11,said ion being selected from the group consisting of Fe, Zn, Cu, Mn, Mg,Co, Ni, Al, V or Ca ion.
 13. The method of claim 1, further includingthe step of applying said polymer to the surface of a fertilizerparticle.
 14. The method of claim 1, said polymer applicationsubstantially coating said fertilizer particle.
 15. The method of claim1, including the step of reacting at least one of said reactants with anion to form a complex.
 16. The method of claim 15, said ion beingselected from the group consisting of Fe, Zn, Cu, Mn, Mg, Co, Ni, Al, Vor Ca ion.
 17. A method of forming a polymer comprising the steps of:providing a reaction mixture comprising at least two different reactantsselected from the group consisting of first and second reactants, or amixture of said second reactants, wherein said first reactant is of thegeneral formula

and said second reactant is of the general formula

wherein each R₇ is individually and respectively selected from the groupconsisting of H, OH, C₁-C₃₀ straight, branched chain and cyclic alkyl oraryl groups, C₁-C₃₀ straight, branched chain and cyclic alkyl or arylformate (C₀), acetate (C₁), propionate (C₂), butyrate (C₃), etc. up toC₃₀ based ester groups, R′CO₂ groups, OR′ groups and COOX groups,wherein R′ is selected from the group consisting of C₁-C₃₀ straight,branched chain and cyclic alkyl or aryl groups and X is selected fromthe group consisting of H, the alkali metals, NH₄ and the C₁-C₄ alkylammonium groups, R₃ and R₄ are individually and respectively selectedfrom the group consisting of H, C₁-C₃₀ straight, branched chain andcyclic alkyl or aryl groups, R₅, R₆, R₁₀ and R₁₁ are individually andrespectively selected from the group consisting of H, the alkali metals,NH and the C₁-C₄ alkyl ammonium groups, Y is selected from the groupconsisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V and Ca, and R₈ and R₉are individually and respectively selected from the group consisting ofnothing (i.e., the groups are non-existent), CH₂, C₂H₄, and C₃H₆, eachof said moieties having or being modified to have a total of two COOgroups therein; and polymerizing said reaction mixture to form a polymerhaving recurring polymeric subunits therein with carbonyl-containinggroups.
 18. The method of claim 17, said first reactant being maleicanhydride.
 19. The method of claim 17, said polymerization step beingcarried out by generating free radicals in said reaction mixture. 20.The method of claim 17, said free radical generation step comprising thestep of adding a peroxide to said reaction mixture.
 21. The method ofclaim 17, said free radical generation step comprising the step ofadding a persulfate to said reaction mixture.
 22. The method of claim17, said free radical generation step comprising the step of subjectingsaid reaction mixture to UV light.
 23. The method of claim 17, saidreaction mixture being formed in a solvent selected from the groupconsisting of water and acetone.
 24. The method of claim 17, saidpolymerization step being carried out at a temperature of from about 0Â°C. to about 120Â° C. for a period of from about 0.25 hours to about 24hours.
 25. The method of claim 17, said polymerization step beingcarried out under an inert gas atmosphere.
 26. The method of claim 17,further including the step of drying said polymer to a solid form. 27.The method of claim 17, including the step of reacting said polymer withan ion to form a complex with the polymer.
 28. The method of claim 27,said ion being selected from the group consisting of Fe, Zn, Cu, Mn, Mg,Co, Ni, Al, V or Ca ion.